<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
    <script>
        function getnum(arr, flag) {
            let num = 0
            for (let i = 0; i < arr.length; i++) {
                num += arr[i]
            }
            if (flag) {
                return num
            } else {
                return num / arr.length
            }
        }
        console.log(getnum([1, 2, 3, 4, 5]));
        console.log(`和为：${getnum([1, 2, 3, 4, 5], true)}`);
        console.log(`平均值：${getnum([1, 2, 3, 4, 5], false)}`)
    </script>
</body>

</html>